Evaluating Ecological Restoration Success: A Review of the Literature
TL;DR: This article conducted a literature review to determine trends in evaluations of restoration projects and identify key knowledge gaps that need to be addressed, and quantified the extent that key attributes of success, including ecological (vegetation structure, species diversity and abundance, and ecosystem functioning) and socioeconomic, were addressed by these papers along with trends in publication and restoration characteristics.
Abstract: Assessing the success of ecological restoration projects is critical to justify the use of restoration in natural resource management and to improve best practice. Although there are extensive discussions surrounding the characteristics that define and measure successful restoration, monitoring or evaluation of projects in practice is widely thought to have lagged behind. We conducted a literature review to determine trends in evaluations of restoration projects and identify key knowledge gaps that need to be addressed. We searched the Web of Knowledge plus two additional restoration journals not found in the database for empirical papers that assessed restoration projects post-implementation. We quantified the extent that key attributes of success, including ecological (vegetation structure, species diversity and abundance, and ecosystem functioning) and socioeconomic, were addressed by these papers along with trends in publication and restoration characteristics. Encouragingly, we found the number of empirical evaluations has grown substantially in recent years. The increased age of restoration projects and number of papers that assessed ecological functions since previous reviews of the literature is also a positive development. Research is still heavily skewed toward United States and Australia, however, and identifying an appropriate reference site needs further investigation. Of particular concern is the dearth of papers identified in the literature search that included any measure of socioeconomic attributes. Focusing future empirical research on quantifying ecosystem services and other socioeconomic outcomes is essential for understanding the full benefits and costs of ecological restoration and to support its use in natural resource management.
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TL;DR: This review of conceptual developments in restoration ecology over the last 30 years is reviewed in the context of changing restoration goals which reflect increased societal awareness of the scale of environmental degradation and the recognition that inter-disciplinary approaches are needed to tackle environmental problems.
Abstract: Simultaneous environmental changes challenge biodiversity persistence and human wellbeing. The science and practice of restoration ecology, in collaboration with other disciplines, can contribute to overcoming these challenges. This endeavor requires a solid conceptual foundation based in empirical research which confronts, tests and influences theoretical developments. We review conceptual developments in restoration ecology over the last 30 years. We frame our review in the context of changing restoration goals which reflect increased societal awareness of the scale of environmental degradation and the recognition that inter-disciplinary approaches are needed to tackle environmental problems. Restoration ecology now encompasses facilitative interactions and network dynamics, trophic cascades, and above- and below ground linkages. It operates in a non-equilibrium, alternative states framework, at the landscape scale, and in response to changing environmental, economic and social conditions. Progress has been marked by conceptual advances in the fields of trait-environment relationships, community assembly, and understanding the links between biodiversity and ecosystem functioning. Conceptual and practical advances have been enhanced by applying evolving technologies, including treatments to increase seed germination and overcome recruitment bottlenecks, high throughput DNA sequencing to elucidate soil community structure and function, and advances in satellite technology and GPS tracking to monitor habitat use. The synthesis of these technologies with systematic reviews of context dependencies in restoration success, model based analyses and consideration of complex socio-ecological systems will allow generalizations to inform evidence based interventions. Ongoing challenges include setting realistic, socially acceptable goals for restoration under changing environmental conditions, and prioritizing actions in an increasingly space-competitive world. Ethical questions also surround the use of genetically modified material, translocations, taxon substitutions, and de-extinction, in restoration ecology. Addressing these issues, as the Ecological Society of America looks to its next century, will require current and future generations of researchers and practitioners, including economists, engineers, philosophers, landscape architects, social scientists and restoration ecologists, to work together with communities and governments to rise to the environmental challenges of the coming decades.
385 citations
Cites background from "Evaluating Ecological Restoration S..."
...…and their services can be seen as having important socio-economic benefits (e.g., job creation, farm income) that have only recently begun to be factored into assessments of restoration success (Aronson et al. 2010, NielsenPincus and Moseley 2013, Wortley et al. 2013) and thus cost effectiveness....
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TL;DR: The science underpinning contemporary approaches to forest restoration practice is synthesized and some major approaches for altering structure in degraded forest stands are presented, and approaches for restoration of two key ecosystem processes, fire and flooding are described.
370 citations
Cites background from "Evaluating Ecological Restoration S..."
..., 2006) but monitoring deficiencies is a common problem (Wortley et al., 2013)....
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TL;DR: In the field of river restoration, a plethora of new studies worldwide provide data on why and how rivers are being restored as well as the project outcomes as mentioned in this paper, and though there is well-accepted theory to support this, research on methods to implement and assess functional restoration projects is in its infancy.
Abstract: Ecological restoration has grown rapidly and now encompasses not only classic ecological theory but also utilitarian concerns, such as preparedness for climate change and provisioning of ecosystem services. Three dominant perspectives compete to influence the science and practice of river restoration. A strong focus on channel morphology has led to approaches that involve major Earth-moving activities, such as channel reconfiguration with the unmet assumption that ecological recovery will follow. Functional perspectives of river restoration aim to regain the full suite of biogeochemical, ecological, and hydrogeomorphic processes that make up a healthy river, and though there is well-accepted theory to support this, research on methods to implement and assess functional restoration projects is in its infancy. A plethora of new studies worldwide provide data on why and how rivers are being restored as well as the project outcomes. Measurable improvements postrestoration vary by restoration method and measur...
353 citations
Cites background from "Evaluating Ecological Restoration S..."
...2013), but measures of biological diversity, abundance, and ecosystem processes remain the indicators most commonly recommended for field assessments of restoration outcomes (Wortley et al. 2013)....
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...Most stream restoration projects today are implemented with a primary focus on channel form or physical structures rather than on ecological processes (Lake et al. 2007, Wortley et al. 2013)....
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...Revisions and updates have been suggested (Shackelford et al. 2013), but measures of biological diversity, abundance, and ecosystem processes remain the indicators most commonly recommended for field assessments of restoration outcomes (Wortley et al. 2013)....
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TL;DR: A meta-analysis encompassing 221 study landscapes worldwide reveals forest restoration enhances biodiversity by 15–84% and vegetation structure by 36–77%, compared with degraded ecosystems.
Abstract: Two billion ha have been identified globally for forest restoration. Our meta-analysis encompassing 221 study landscapes worldwide reveals forest restoration enhances biodiversity by 15-84% and vegetation structure by 36-77%, compared with degraded ecosystems. For the first time, we identify the main ecological drivers of forest restoration success (defined as a return to a reference condition, that is, old-growth forest) at both the local and landscape scale. These are as follows: the time elapsed since restoration began, disturbance type and landscape context. The time elapsed since restoration began strongly drives restoration success in secondary forests, but not in selectively logged forests (which are more ecologically similar to reference systems). Landscape restoration will be most successful when previous disturbance is less intensive and habitat is less fragmented in the landscape. Restoration does not result in full recovery of biodiversity and vegetation structure, but can complement old-growth forests if there is sufficient time for ecological succession.
347 citations
01 Sep 2007
TL;DR: There is a need to move to a clearer and more systematic approach to habitat restoration that considers appropriate goals linked to target species or suites of species, as well as the ecological, financial, and social constraints on what is possible.
Abstract: The term "habitat restoration" appears frequently in conservation and landscape management documents but is often poorly articulated. There is a need to move to a clearer and more systematic approach to habitat restoration that considers appropriate goals linked to target species or suites of species, as well as the ecological, financial, and social constraints on what is possible. Recommendations for particular courses of action need to be prioritized so that restoration activities can achieve the best result possible within these constraints. There is unlikely to be a generic set of recommendations that is applicable everywhere because actions need to be matched to the particulars of site and situation. However, there is a generic set of questions that can be asked, which can help guide the process of deciding which restoration actions are most important and contribute most to the reestablishment of desirable habitat characteristics within a given project area.
267 citations
References
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University of Michigan1, College of William & Mary2, McGill University3, Western Washington University4, Arizona State University5, Imperial College London6, University of Minnesota7, Swedish University of Agricultural Sciences8, Stanford University9, Centre national de la recherche scientifique10, United States Geological Survey11, University of British Columbia12, Columbia University13
TL;DR: It is argued that human actions are dismantling the Earth’s ecosystems, eliminating genes, species and biological traits at an alarming rate, and the question of how such loss of biological diversity will alter the functioning of ecosystems and their ability to provide society with the goods and services needed to prosper is asked.
Abstract: The most unique feature of Earth is the existence of life, and the most extraordinary feature of life is its diversity. Approximately 9 million types of plants, animals, protists and fungi inhabit the Earth. So, too, do 7 billion people. Two decades ago, at the first Earth Summit, the vast majority of the world's nations declared that human actions were dismantling the Earth's ecosystems, eliminating genes, species and biological traits at an alarming rate. This observation led to the question of how such loss of biological diversity will alter the functioning of ecosystems and their ability to provide society with the goods and services needed to prosper.
5,244 citations
"Evaluating Ecological Restoration S..." refers background in this paper
...Identifying and measuring the socioeconomic benefits provided by ecosystems have been key concerns of biodiversity conservation with substantial work on the economic value of ecosystem services as well as the effect on welfare and community development (Sachs et al. 2009; Cardinale et al. 2012)....
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TL;DR: The three primay attributes of biodiversity recognized by Jerry Franklin are expanded into a nested hierarcby that incorporates ele- ments of each attribute at four levels of organization: re- gional landscape, community-ecosystem, population- species, andgenetic.
Abstract: Biodiversity is presently a minor consideration in environmental policy. It has been regarded as too broad and vague a concept to be applied to real-world regulatoy and managernentproblems. This problem can be corrected ifbio- diversity is recognized as an end in itsea and if measurable indicators can be selected to assess the status of biodiversity over time. Biodiversity, as presently understood, encom- passes multiple levels of biological organization. In thispa- per, I expand the three primay attributes of biodiversity recognized by Jerry Franklin - composition, structure, and function - into a nested hierarcby that incorporates ele- ments of each attribute at four levels of organization: re- gional landscape, community-ecosystem, population- species, andgenetic. Indicators of each attribute in terrestrial ecosystems, at the four levels of organization, are identified for environmental monitoring purposes. Projects to monitor biodiversity will benefit from a direct linkage to long-term ecological research and a commitment to test hypotheses relevant to biodiversity conservation. A general guideline is to proceed from the top down, beginning with a coarse-scale invent0 y of landscape pattern, vegetation, habitat structure, and species distributions, then overlaying data on stress lev- els to identiD biologically significant areas at high risk of impoverishment. Intensive research and monitoring can be directed to high-risk ecosystems and elements of biodiversity, while less intensive monitoring is directed to the total land- scape (or samples thereon. In any monitoringprogram, par- ticular attention should be paid to specifying the questions that monitoring is intended to answer and validating the relationships between indicators and the components of bio- diversity they represent
2,937 citations
"Evaluating Ecological Restoration S..." refers background in this paper
...The attributes cover three general ecological outcomes; vegetation structure, species diversity and abundance, and ecological processes (Ruiz-Jaen & Aide 2005a) which are commonly used to classify indicators of ecosystem condition in the literature (Noss 1990; Aronson & LeFloch 1996; Ruiz-Jaen & Aide 2005b)....
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...…cover three general ecological outcomes; vegetation structure, species diversity and abundance, and ecological processes (Ruiz-Jaen & Aide 2005a) which are commonly used to classify indicators of ecosystem condition in the literature (Noss 1990; Aronson & LeFloch 1996; Ruiz-Jaen & Aide 2005b)....
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TL;DR: A meta-analysis of 89 restoration assessments in a wide range of ecosystem types across the globe indicates that ecological restoration increased provision of biodiversity and ecosystem services by 44 and 25%, respectively, however, values of both remained lower in restored versus intact reference ecosystems.
Abstract: Ecological restoration is widely used to reverse the environmental degradation caused by human activities. However, the effectiveness of restoration actions in increasing provision of both biodiversity and ecosystem services has not been evaluated systematically. A meta-analysis of 89 restoration assessments in a wide range of ecosystem types across the globe indicates that ecological restoration increased provision of biodiversity and ecosystem services by 44 and 25%, respectively. However, values of both remained lower in restored versus intact reference ecosystems. Increases in biodiversity and ecosystem service measures after restoration were positively correlated. Results indicate that restoration actions focused on enhancing biodiversity should support increased provision of ecosystem services, particularly in tropical terrestrial biomes.
1,355 citations
"Evaluating Ecological Restoration S..." refers background in this paper
...Rey-Benayas, J. M., A. C. Newton, A. Diaz, and J. M. Bullock....
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...In the restoration literature, Bullock et al. (2011), Rey-Benayas et al. (2009), and Palmer and Filoso (2009) along with many others have discussed the benefit of assigning an economic value to ecosystem services recovered through restoration, whereas Geist and Galatowitsch (1999), Miller and Hobbs (2007), and Le et al. (2012) highlight the significant role of social influences in achieving restoration success....
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...In the restoration literature, Bullock et al. (2011), Rey-Benayas et al. (2009), and Palmer and Filoso (2009) along with many others have discussed the benefit of assigning an economic value to ecosystem services recovered through restoration, whereas Geist and Galatowitsch (1999), Miller and Hobbs…...
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...Bullock, J. M., J. Aronson, A. C. Newton, R. F. Pywell, and J. M. Rey-Benayas....
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TL;DR: This work stresses the importance of developing restoration methodologies that are applicable at the landscape scale, beyond nonquantitative generalities about size and connectivity, so that urgent large-scale restoration can be planned and implemented effectively.
Abstract: Heightening human impacts on the Earth result in widespread losses of production and conservation values and make large-scale ecosystem restoration increasingly urgent. Tackling this problem requires the development of general guiding principles for restoration so that we can move away from the ad hoc, site- and situation-specific approach that now prevails. A continuum of restoration efforts can be recognized, ranging from restoration of localized highly degraded sites to restoration of entire landscapes for production and/or conservation reasons. We emphasize the importance of developing restoration methodologies that are applicable at the landscape scale. Key processes in restoration include identifying and dealing with the processes leading to degradation in the first place, determining realistic goals and measures of success, developing methods for implementing the goals and incorporating them into land-management and planning strategies, and monitoring the restoration and assessing its success. Few of these procedures are currently incorporated in many restoration projects. The concept that many ecosystems are likely to exist in alternative stable states, depending on their history, is relevant to the setting of restoration goals. A range of measures, such as those being developed to measure ecosystem health, could be used to develop “scorecards” for restoration efforts. Generalizable guidelines for restoration on individual sites could be based on the concepts of designed disturbance, controlled colonization, and controlled species performance. Fewer explicit guidelines are available at the landscape scale, beyond nonquantitative generalities about size and connectivity. Development of these guidelines is an important priority so that urgent large-scale restoration can be planned and implemented effectively.
1,227 citations
TL;DR: Practical restoration efforts should rely heavily on what is known from theoretical and empirical research on how communities develop and are structured over time, and are identified specific areas that are in critical need of further research to advance the science of restoration ecology.
Abstract: Community ecological theory may play an important role in the development of a science of restoration ecology. Not only will the practice of restoration benefit from an increased focus on theory, but basic research in community ecology will also benefit. We pose several major thematic questions that are relevant to restoration from the perspective of community ecological theory and, for each, identify specific areas that are in critical need of further research to advance the science of restoration ecology. We ask, what are appropriate restoration endpoints from a community ecology perspective? The problem of measuring restoration at the community level, particularly given the high amount of variability inherent in most natural communities, is not easy, and may require a focus on restoration of community function (e.g., trophic structure) rather than a focus on the restoration of particular species. We ask, what are the benefits and limitations of using species composition or biodiversity measures as endpoints in restoration ecology? Since reestablishing all native species may rarely be possible, research is needed on the relationship between species richness and community stability of restored sites and on functional redundancy among species in regional colonist “pools.” Efforts targeted at restoring system function must take into account the role of individual species, particularly if some species play a disproportionate role in processing material or are strong interactors. We ask, is restoration of habitat a sufficient approach to reestablish species and function? Many untested assumptions concerning the relationship between physical habitat structure and restoration ecology are being made in practical restoration efforts. We need rigorous testing of these assumptions, particularly to determine how generally they apply to different taxa and habitats. We ask, to what extent can empirical and theoretical work on community succession and dispersal contribute to restoration ecology? We distinguish systems in which succession theory may be broadly applicable from those in which it is probably not. If community development is highly predictable, it may be feasible to manipulate natural succession processes to accelerate restoration. We close by stressing that the science of restoration ecology is so intertwined with basic ecological theory that practical restoration efforts should rely heavily on what is known from theoretical and empirical research on how communities develop and are structured over time.
1,015 citations
"Evaluating Ecological Restoration S..." refers result in this paper
...much can be inferred about an ecosystem from the structural attributes (Palmer et al. 1997) and recent studies have demonstrated results can vary considerably between observers (Cheal 2008; Gorrod & Keith 2009; Kelly et al....
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...…2006), there are questions as to how 540 Restoration Ecology SEPTEMBER 2013 much can be inferred about an ecosystem from the structural attributes (Palmer et al. 1997) and recent studies have demonstrated results can vary considerably between observers (Cheal 2008; Gorrod & Keith 2009; Kelly et…...
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